11:59,
March 9, 2016

Today I needed to figure out how to mirror 100% of inbound HTTP/HTTPS traffic to a second cluster of backend servers, whilst not disrupting the production
traffic going to the primary cluster.

There's lots of tools to do things like this, for example duplicator and
teeproxy and parallel-proxy. But those are all "code I found on the
internet" and possibly questionable, and in some cases, written in node.js,
which I don't know if I consider "mature" or "robust" enough for production
traffic.